Apparatus and method for manufacturing optical objects

ABSTRACT

The invention relates to an apparatus for forming or working optical elements and/or optical forming elements ( 1 ) comprising a working apparatus ( 18 ) for forming surfaces of form parts by machining or an abrasive technique, wherein at least one measuring device ( 17 ) is provided for measuring changes in form and/or surface roughness of said surface when said surface is being worked and, on the basis thereof controlling said working apparatus ( 18 ).

This application is the U.S. National Phase of International ApplicationNumber PCT/NL2003/000946 filed on Dec. 30, 2003, which is incorporatedherein by reference.

The invention relates to an apparatus for forming or working opticalelements and/or optical forming elements.

The invention further relates to a method for forming or working opticalelements and/or forming elements.

Further, the invention relates to optical elements or forming elementstherefor such as molds.

BACKGROUND OF THE INVENTION

It is known from practice to manufacture optical elements and/or formingelements such as lenses, spectacle glasses, molds and the like from apre-form, manufactured from, for instance, organic or mineral glasswhich pre-form, on a first side, has a substantially flat or slightlyconcave, spherical surface with a relatively large bending radius, and,on a second, opposite side, a convex surface with a relatively smallbending radius. The convexity of, in particular, the second surface isselected depending on the strength of the desired eventual element suchas frame, frame curve and glass curve and of the power of a spectacleglass with respect to myopia (nearsightedness) and hyperopia.

The first surface of this pre-form is milled in a milling machinesuitable to that end, while the pre-form is rotated at high speed andthe central thickness is reduced and a spherical surface is milled away,so that the radius of the concave surface is reduced. After,approximately, the desired form is obtained, the resulting surface isground and polished, in order to obtain the desired shape and finish.This polishing is done with a polishing form which is pressed againstthe surface and which approximately has the desired ultimate shape,whereupon optical element and/or polishing form are rotated relative toeach other.

In this known method, relatively much material is removed while duringpolishing, each time, the polishing form is to be removed to enablemeasurement and examination of the surface and central thickness,whereupon, if desired, polishing is continued before the optical elementis removed from the blocker. This is why this manufacturing method isrelatively expensive, labor intensive, time consuming and not alwayssufficiently accurate. Use of a polishing form is then disadvantageousbecause with it, at least on a first side, only symmetrically ground,substantially spherical or toric surfaces with parabolic or hyperboliccross sections can be obtained. Further, this method is not particularlysuitable for grinding and polishing highly concave surfaces.

Further, it is known from practice to use pre-form optical elementswhich, on the whole, already have the outer contour of the desiredoptical element. Here, both the first (aspherical) and the secondsurface (aspherical or toric) are of curved design, and by substantiallyadding material or removing through polishing, in the above-describedmanner, the curvature of the concave side of the pre-form can be adaptedso as to obtain the desired optical element, particularly intended fornearsightedness or semi-nearsightedness. For this method too, it holdsthat it is relatively expensive and time-consuming and, moreover, notalways sufficiently accurate, while furthermore, each time, intermediatemeasurements are to be performed, during which the element is to betaken from a holder and the operation is to be stopped.

In this description, optical elements are at least understood toinclude, in particular, spectacle glasses and contact lenses but alsooptical elements such as lenses for (precision) optics, mirrors and thelike. Optical forming elements are at least understood to includeforming elements such as molds, machining and non-machining foldingtools and the like. The optical elements, optical forming elements andpre-forms thereto may together be indicated as optical objects. Theexamples given hereinabove should not be construed to be limitative inany way.

The invention contemplates an apparatus for forming and/or workingoptical elements and/or optical forming elements, with which at least anumber of the drawbacks of the state of the art can be obviated.

A further object of the invention is to provide such an apparatus withwhich optical elements and/or forming elements can be manufacturedand/or worked in a rapid and reliable manner.

A further object according to the invention is to provide such anapparatus with which from a limited number of pre-forms, a large numberof different optical elements can be obtained.

A further object of the invention is to provide such an apparatus withwhich indication means, identification means and the like can beprovided.

A still further object of the invention is to provide in an apparatuswith which optical elements, in particular spectacle glasses and/orcontact lenses can be made to measure, in particular matching eyedimensions and/or frame dimensions.

The invention further contemplates providing methods for accuratelymanufacturing or working optical elements and/or optical formingelements, in particular relatively complex elements in a simple andrapid manner.

The invention further contemplates providing optical elements and/oroptical forming elements with relatively complex shapes and surfaces.

These and many objects are achieved according to the invention with theaid of an apparatus, method and optical (forming) element, respectively,as embodied in the claims.

SUMMARY OF THE INVENTION

With an apparatus according to the invention are provided:

-   -   a working apparatus for forming, at least working, surfaces of        form parts such as pre-forms, lenses, molds and the like by a        machining or, preferably, an abrasive technique;    -   at least one measuring device with which, when a surface is        being worked, changes in form and/or changes in surface        roughness of this surface can be measured; and    -   means for operating the working apparatus on the basis of the        measured changes.

With an apparatus according to the invention, during working of asurface, instantaneously, in situ, the change in form and/or surfaceroughness can be determined by, for instance, measuring changes inthickness and/or in surface roughness, so that, each time, the workingapparatus can be controlled in a suitable manner for obtaining thedesired local change of the respective surface. As a result, operationscan be carried out rapidly and efficiently, milling, grinding and/orpolishing operations can, for instance, be integrated, the element to beformed needs not be removed repeatedly and/or the operation needs not bestopped for carrying out measurements. Moreover, thus, the advantage isachieved that the element to be formed does not change positions when itis worked, so that, relative to one initial form, measuring and workingcan take place both absolutely and relatively, thereby increasing theversatility of the apparatus and the accuracy of the operations.

Preferably, each time, measuring takes place there where the workingapparatus performs an operation, or in the direct vicinity thereof. Morein particular, a relatively large part of the surface, preferablyvirtually the entire surface to be worked is measured so that, eachtime, the form of the entire surface can be monitored. With this, theadvantage can be achieved that, for instance, changes in form onpositions where no working takes place can also be observed and that theworking apparatus can take this into account when working further.

With an apparatus according to the invention, preferably, use is made oflight in the measuring device, more in particular interferencemeasurements and/or scatterometry. In particular with optical elementsand optical forming elements, this has proven particularly advantageoussince refraction and reflection by the optical elements allowinterference measurements and scatterometry particularly well.

With an apparatus according to the invention, preferably, the workingapparatus is provided with at least one jet nozzle from which, underpressure, a blasting agent can be dispensed for an abrasive operationsuch as forming and polishing. Such a device can for instance be a jetstream polishing device. As a blasting agent, use can be made of a fluidwith an abrasive agent included therein such as oxides, sand, glass,ice, mineral, ceramic, metal, allow or such particles, which can, forinstance, be selected according to whether a machining property or apolishing property is desired. With such a device, abrasive operationcan be carried out, also locally, in a rapid and accurate manner,without the respective surface as a whole needing to have a rotationalsymmetry. Also, powder jet techniques can be used.

Preferably, the apparatus is provided with a holder for the object to beworked, which holder is at least partly translucent, the measuringdevice being arranged for measuring, through the holder and the object,changes in form, in particular in the surface facing away from theholder. With this, in a particularly simple manner, measurement ofsurface changes can be carried out on the position where an operation iscarried out or in the direct vicinity thereof. The fact is that thelight, at least the waves with which the measurement is carried out,needs not pass the machining apparatus. By including at least one lensin the holder, in particular a Fresnel lens, the additional advantage isachieved that the measuring device can be designed to be particularlysmall and compact and, as a whole, can measure a relatively large objectthrough a relatively small holder.

In an apparatus according to the invention, milling means, polishingmeans, grinding means and the like can be provided and preferably acombination thereof, more in particular such that with the differentdevices, operations can be carried out on one optical object, withoutthis, intermediately, needing to be intermediately repositioned relativeto the measuring device. An apparatus according to the invention can beused for both conventional operations and the working methods describedhereinabove. As a result, rapidly and efficiently, a number ofoperations can be performed in sequence.

Use of a jet polishing means offers the advantage that operations on thesurface can be carried out accurately and relatively locally, so thatfor instance recesses of limited dimensions can be provided, surfaceparts of relatively small sizes can be removed and the like. With anexact measurement and a relatively simple operation, a desired precisionfor the respective optical means can already be obtained. Also, withthis, the advantage is achieved that the optical object and/or theworking device such as a milling head, grinding head or polishing headneeds not be rotated for the operation, at least not over a multiple of360 degrees, so that non-rotation symmetrical objects can also be formedor worked.

With an apparatus according to the invention, for instance also a greatvariety of multi-focal lenses can be manufactured from a limited numberof pre-forms. The fact is that starting from a standard pre-form, havingor not having an aspherical portion, with the aid of a device, materialcan be removed locally, so that there, the refraction of the lens can beadjusted, so that a, for instance, principally negative lens can be mademore or less negative or even positive, or the other way around. As aresult of the use of an abrasive device, in particular a jet polishingdevice, relatively deep and local recesses can be provided, with anydesired form and size, while with the aid of the measuring device, eachtime in situ, the change in form can be determined and adjusted.

In a comparable manner and with comparable means, also, metal or glassmolds, required for the manufacture of pre-forms can be obtained, atleast worked.

It is then preferred, that with an apparatus according to the invention,also lenses or the like can be made to measure for, for instance, aframe of a pair of spectacles or of an optical instrument. With this, inone apparatus, leases can be ready-made to be placed by or for an enduser.

Preferably, damping means, at least vibration insulating means areprovided which prevent the measuring device from being affected byvibrations generated by the working apparatus. These means can forinstance be active vibration dampers, such as low frequency active orhigh frequency active dampers, white furthermore, the working apparatusand/or the measuring device and/or the holder for the object to beworked can be arranged separate from each other, for instance on one ormore robot arms, which are arranged in a vibration low relation relativeto each other.

The working apparatus can be provided with several jet openings forworking different parts of a surface simultaneously, while the measuringmeans are arranged for measuring the changes in form, at leastreductions in thickness on each of the positions where operations arecarried out, and adjusting, individually or group-wise, the respectiveblow openings, at least jets exiting therefrom, for instance byadjusting flow rate, speed, direction and/or pressure or such parametersof a blasting device, preferably with known, specifically definedoutflow pattern and surface, in particular a jet polishing device.

The invention further relates to a method for working optical elementsand/or optical forming elements, wherein an optical element is placed inor on a holder such that a surface to be worked lies substantially clearfrom the holder, whereupon, with the aid of a working apparatus designedfor carrying out an abrasive method, said surface to be worked is workedsuch that at least locally, the thickness of the element decreases whilesimultaneously, the thickness of the element at least at the location ofthe momentaneously worked surface part is measured and the workingapparatus is controlled on the basis of the measured thickness, at leastreduction thereof as a result of the abrasive method.

With such a method, rapidly, simply and accurately, optical objects canbe worked and/or formed.

The invention further relates to optical objects provided with a firstsurface and an opposite, second curved surface, wherein on the secondsurface, locally, an elevation has been provided while in the firstsurface, approximately opposite said elevation, a recess and/orprotuberance has been provided. Additionally, the first and the secondsurface can be of curved design, concave and convex, respectively, andsubstantially of spherical, toric, parabolic or hyperbolic shape eachwith an apex, while the elevation and/or the recess and/or theprotuberance have been provided at a distance from the apex.

In the further subclaims, further advantageous embodiments of anapparatus, method and optical objects according to the invention aredescribed.

BRIEF DESCRIPTION OF THE DRAWINGS

In clarification of the invention, embodiments of apparatus, methods andoptical objects according to the invention will be further describedwith reference to the drawing, which are only shown by way ofillustration and should not be construed to be limitative in any manner.In the Figures:

FIG. 1 shows a cross section of a first embodiment of a pre-form for anoptical element;

FIG. 2 shows a cross section of a second embodiment of a pre-form for anoptical element;

FIG. 3 shows a cross section of a third embodiment of a pre-form for anoptical element;

FIG. 4 shows a cross section of a fourth embodiment of a pre-form for anoptical element;

FIG. 5 shows, in top plan view, a pre-form or optical element accordingto any one of FIGS. 1-4, in particular according to FIG. 3 or 4;

FIG. 6 schematically shows an apparatus according to the invention, in afirst embodiment;

FIG. 7 schematically shows a part of an apparatus according to theinvention, in a second embodiment;

FIGS. 7A-D schematically show four embodiments of an apparatus accordingto FIG. 7;

FIG. 8 schematically shows, in partly cross-sectional side view, a partof an apparatus according to the invention; in particular of a holderwith measuring device and working means;

FIG. 9 schematically shows, in partly cross-sectional side view, a partof an apparatus according to the invention, in particular of analternative embodiment of a holder with measuring device and workingmeans;

FIG. 10A-E show five configurations of set-ups of a working apparatus, ameasuring device and a holder for an optical element or pre-formaccording to the invention;

FIG. 11 schematically shows a further alternative embodiment of anapparatus according to the invention;

FIG. 12 shows, in top plan view and cross-sectional side view a first,male part of an optical forming element, in particular a mold for acontact lens;

FIG. 13 shows, in top plan view, an optical element from which a lenscan be taken, provided with coating and profiles; and

FIG. 14 shows, in cross-sectional side view, an element according to theline XIV-XIV of FIG. 13.

DETAILED DESCRIPTION OF THE INVENTION

In this description, identical or corresponding parts have identical orcorresponding reference numerals. In this description, as examples,mainly apparatus and methods are described for forming optical objectssuch as lenses, more in particular ophthalmic objects such as spectacleglasses and contact lenses, and forming elements therefor such as moldsand parts thereof. However, such apparatus and methods can also be usedfor other optical elements, for instance precision optics, mirrors andthe like. Optical elements and optical forming elements also be furtherindicated as optical objects. The optical objects shown in the drawinghave substantially circular aspects. From them, if desired, finalobjects such as spectacle glasses can be cut. However, the opticalobjects and the pre-forms therefor can naturally also have differentforms.

In FIG. 1, a pre-form 1 for an optical element is shown, in crosssection. This pre-form 1 is manufactured from, for instance, transparentplastic such as polycarbonate or from glass, and has a curved firstsurface 2 with a first bending radius R1 and a second surface 3, alsocurved, with a second bending radius R2. By varying the bending radiusesR1 and R2, naturally, the power of the pre-form, at least the opticalelement 1 can be determined and varied. In this embodiment, the firstand second surface 2, 3 are substantially spherical, at least, have,substantially, a parabola or hyperbola as cross-sectional aspect, whilethe first surface 2 is concave and the second surface 3 is convex.

In FIG. 2, a first alternative embodiment of a pre-form 1 according tothe invention is shown, wherein the first surface 2 is substantiallyflat and the second surface 3 is curved, with a bending radius R3 suchthat this is convex. Herein, particularly with parabolic or hyperboliccross sections, bending radius R is understood to include the localbending radius of a surface segment in the respective surface 2, 3.

Naturally, the first and or second surfaces of the pre-forms shown can,as desired, be of convex and/or concave design.

In FIG. 3, in cross-sectional view, a third embodiment of a pre-form 1according to the invention is shown, comparable to that of FIG. 1,wherein, however, on the second surface, at a distance A from the apex 4thereof, an elevation 5 is provided, a protuberance which is integrallyformed with the pre-form. The height H of this elevation can be selectedas desired. It will be clear that the refraction at the height of theelevation 5 will be different from that of parts located immediatelynext to it of the optical element.

In FIG. 4 in cross-sectional side view, a pre-form 1 is shown,comparable to that according to FIG. 2, wherein, however, once more, anelevation 5 is provided on the second surface 3, at a distance from theapex 4, once more with a height H to be selected as desired.

FIG. 5 shows, in top plan view, a pre-form 1 according to any one ofFIGS. 1-4, wherein, in interrupted lines, a possible contour 6 of theelevation 5 is shown. Naturally, this contour can have any suitableform, as can the cross section of the elevation, depending on theoptical element to be formed.

From a pre-form 1 according to any one of FIGS. 1-4, an optical elementcan be formed by making it to measure with the aid of, for instance,milling, grinding and polishing techniques. From the pre-form 1according to FIG. 2 or 4, in a known manner, a large part is then milledaway from the side of the first surface, so that a concave first surface2A is obtained as drawn in FIGS. 2 and 4 in interrupted lines. Accordingto the invention, preferably, in the first surface 2, 2A, a recess 7 isprovided at a distance B from the apex 4A of the respective surface, sothat locally, the refraction of the optical element (the pre-form 1and/or an object such as a spectacle glass to be formed therefrom) isinfluenced. Naturally, in a comparable manner, instead thereof or inaddition thereto, a recess can be provided in the opposite secondsurface 3.

In the embodiment shown in FIGS. 3 and 4, the first surface is ofcontinuous design, i.e. without recess, since on the opposite, secondsurface 3, an elevation 5 has already been provided. However, also inthese embodiments, a recess 7 can be provided, as schematicallyindicated by the broken line 8, for further influencing the refractionof the optical element. The distances A and B can then be selected to besuch that the recess and elevation 7, 5 are located directed one abovethe other, but also such, that they are slightly shifted relative toeach other, for influencing the refraction in a specific manner.

Use of recesses 7 and/or elevations 5 according to the invention offerthe advantage that, particularly, multifocal lenses such as spectacleglasses can be manufactured, while moreover, from a particularly smallnumber of types of pre-forms a particularly great variety of lenses canbe manufactured, to measure for the intended use. For instance,approximately one fifth of the normally required number of pre-forms cansuffice. Naturally, also the elevation 5 can be adjusted by removing oradding material.

Pre-forms can be worked with standard working methods such as millingand polishing, but it is preferred that an apparatus according to theinvention be used such as shown in, for instance, FIG. 6, 7 or 11,details of which are shown in the further Figures.

In FIG. 6, schematically, an apparatus 10 according to the invention isshown, with which pre-forms 1 can be worked in a simple and accuratemanner. This apparatus 10 comprises a table 11 which can be rotated by ashaft 12 which is driven by a motor 13. The shaft 12 extends through thebottom of a tray 14, in which it is mounted by way of bearing 15. Thetable 11 extends above the tray 14 and is provided at the top side witha holder 16 as will be further described, on which, with means suitableto that end, an optical element such as a pre-form 1 can be secured, forinstance with an adhesive compound/component. In or on the table 11,measuring means 17 are included with which in situ changes in form andparticularly in thickness in the optical element can be measured. Thesemeasuring means will be further elucidated.

For measuring surface roughness and/or changes therein, in anadvantageous manner, use can be made of scatterometry, instead of or inaddition to interference measurement.

The apparatus 10 is further provided with a working device 18 forabrasively working the optical element, in particular in aforce-controlled manner. In particular, as an example, a fluid jetdevice 19 is shown, in particular suited for polishing. This device 19comprises a holder 20 for a liquid blasting agent 21, for instance amixture of a liquid such as water and an abrasive agent such as sand,glass, ice, oxides, mineral, ceramic, metal, alloys, metal powder,plastic or such blasting agents known per se. The nature and size of theparticles, at least of the blasting agent can for instance be selectedaccording to whether, in particular, a machining property or,conversely, a polishing property is desired. To the holder a duct 22 isconnected which is connected, via a pump 23, to a jet nozzle 24 withwhich, under pressure, a blasting agent 21 can be projected to theoptical element for abrasively working this, in particular abstractingmaterial therefrom for forming, for instance, a recess 7, for locallyadjusting the bending radius R and/or influencing the surface roughness.The blasting agent 21 can be collected in the tray 14 and be returned tothe holder 20. Such an device 19 offers the advantage that with it, inan accurate and rapid manner, surfaces can be worked particularlylocally, for instance for forming recesses 7 with relatively large depthand small surface, or adjusting elevations 5.

In an alternative embodiment, with the aid of a known powder jettechnique, the or a surface can be pre-treated. Powder blasting offersthe advantage that with this, in a rapid and simple manner, a relativelyrough operation can be carried out whereafter, in the manner describedhereinabove, the desired form and/or surface roughness can be obtained.

In FIG. 7, an alternative embodiment of a part of a jet device 19according to the invention is shown, wherein a series of jet nozzles 24is shown, each connected, via a pump 23, to a holder 20 for blastingagent 21. Between each pump 23 and jet nozzle 24, a control valve orsuch control member 25 is provided with which, separately, the abrasiveprocess can be adjusted. The fact is that with the aid of a control unit26, as shown in FIG. 6 too, the pumps 23, control valves 25 and jetnozzles 24 can be controlled, for instance for controlling pressure,flow rate, blasting/jet direction and the like. With such a device alarger surface can be worked more rapidly. To that end, the jet nozzles24 are fitted on drivable pivot means 27.

Naturally, groups of jet nozzles 24 can also be driven together. Byadjusting or exchanging the jet nozzles 24, the outflow profiles and,hence, the working surfaces can be adjusted.

In FIGS. 7A-D, schematically, four embodiments of an apparatus accordingto FIG. 7 are shown.

FIG. 7A shows an embodiment wherein a matrix of jet nozzles 24, forinstance jet openings, is included in a plate-shaped part 24A. An object1 to be worked is arranged beneath it. As appears from the Figure, thejet nozzles 24 have a conical blasting pattern 24B such that the entiresurface of the object 1 is contacted by it. With it, an entire surfacecan be worked in one go. Optionally, the part 24A can be adjusted inform to the surface to be worked, for instance with a comparableelevation or recess, so that each time, the distance between the jetnozzles 24 and the surface remains approximately the same. The plate 24Acan be arranged for rotation about a normal-axis on the surface or bemovable in its own plane (arrow P₁) so that a random effect can beobtained. With this, rapidly and simply, an entire surface can beworked.

FIG. 7B shows an embodiment comparable to that shown in FIG. 7A,wherein, however, only one row of jet nozzles 24 is provided in a plate24A. The plate and/or the object 1 are moved in the direction P₂relatively to each other for obtaining the desired working. With this,rapidly and simply, a surface can worked and simple adjustment in theform can be obtained.

FIG. 7C shows an embodiment wherein the jet nozzles are provided in aplate 24A approximately in concentric circles. Here, the plate ispreferably movable in two directions P1, P2 at right angles to eachother, and pivotable in two direction Z1, Z2. As a result, a controlledmovement of the plate and thus of the jets 24B over the surface ispossible, so that forming the surface can be carried out in a rapid,simple and accurate manner.

FIG. 7D shows an embodiment wherein, in a plate-shaped part 24A, aseries of jet nozzles, individually drivable and adjustable at least indirection of jet and pattern is provided, so that with plate 24A andobject 1 stationary or moving relative to each other, desired surfaceoperations such as forming and finishing can be carried out. Anadvantage is that object and plate need not be moved.

With each of the embodiments as shown in FIG. 7, 7A-7D, if desired, thejet nozzles can be drivable individually or group-wise and be providedwith, for instance, a control valve 25 and/or pump 23, connected to thecontrol device 26. With this, the pattern of working can be controlledeven better.

When the optical object such as the pre-form 1 is being worked, with theaid of the measuring device 17, each time, there where an operation iscarried out with the working apparatus and/or in the direct vicinitythereof, the change in the surface on which the operation is carried outis measured, preferably continuously. To that end, the measuring deviceis designed as a contactless measuring device such as an interferometricmeasuring device. A device can then be used with which the entiresurface is measured virtually completely and in one go, as schematicallyshown in FIG. 8, or locally, as schematically shown in FIG. 9. Suchmeasuring devices and methods are, for that matter, known per se and usechanges in reflection and waves destroying or reinforcing each other, inparticular light. Herewith, in particular, relative reductions inthickness of the optical element can be measured during working andpreferably through the object, from a side on which no workingoperations are carried out. Preferably, the device 17 according to theinvention is provided with means for establishing the initial positionof the object, in particular the pre-form 1, on the holder 16, and fordetermining the original shape of the pre-form 1, for instance throughthe use of 3-D position determination, stereo photography or suchmethods known per se, so that, each time, from the relative changes inthickness and form the actual thickness and form are known, at least canbe determined. What can be achieved with such a measuring device 17 isthat during working, the pre-form 1, at least the optical element needsnot be taken from the holder 16 but can be worked in a continuousprocess.

In the embodiment shown in FIG. 9, the device 17 is provided with twotransmitter-receivers 28 for light, with which, through the holder 16,preferably of transparent design according to the invention, and theoptical object 1 (the pre-form), light beams 29 can be transmitted andreceived. The light beams are at least partially reflected by thesurface to be worked of the optical object 1, in the exemplaryembodiment shown the second surface 3, so that, through interference ofthe two light beams 29A, 29B, the changes in form, in particular thechanges in thickness can be determined, while moreover, the surfaceroughness can be determined and verified. The transmitter-receivers 28can be pivoted about axes 30A, 30B, so that the entire surface 3 can becovered. The transmitter-receivers 28 and the nozzle 24 are driven bythe control device 26 with which, on the basis of a desired profileentered into the control device 26, for each part of the surface 3, thedevice 10 can be controlled and can be adjusted in a continuous manner.

In the embodiment shown in FIG. 8, the device 17 is included in a hollowshaft 12, at least the transmitter-receivers 28. Adjacent the top end ofthe shaft, a lens or an assembly of lenses 31 is arranged, in particulara Fresnel lens 31, with which light of the transmitter-receivers 28 canbe deflected through the transparent holder 16 and the optical object 1.The holder 16 is fixed in a known manner, schematically shown by thenotches 34 and complementary protuberances 35. The optical object isattached to the holder 16 in a position retaining manner with the aid ofan agent 32 suitable thereto such as an adhesive paste, while the holderfunctions as a blocker. Suitable as an agent 32, but not limited theretois, for instance, resin curing under UV-light or due to temperaturechange. This agent 32 has a known refractive index, preferably matchingand more preferably approximately equal to that of the holder 16. Withsuch a configuration, directly through the holder 16, which, as a rule,is also indicated as blocker, an image of changes in form and thicknesscan be obtained of virtually the entire surface 2 to be worked, in amanner described hereinabove, on the basis of which the workingapparatus 18, schematically indicated by a jet nozzle 24 of a device 19or a milling device 36, can be driven.

In FIGS. 10A-E, five possible configurations are given for an apparatus10 according to the invention, wherein at least one of the elementsworking apparatus 18, measuring device 17 and/or table 11 with holder 16is moveably arranged with the aid of a robot arm.

In the embodiment shown in FIG. 10A, working device 19, at least the jetnozzle 24 and the measuring device 17 are disposed on two separate robotarms 40A, B, while the table 11 with holder 16 is fixedly disposed. Therobot arms 40 and the table 11 are arranged on the same foundation whilemeans can be provided for damping and/or compensating vibrationsgenerated by the working apparatus 18, for instance through vibrationdampers in the foot 41 of the robot arms 40 and/or the table 11, or byactive vibration compensation and/or damping. Such means aresufficiently known.

In the embodiment shown in FIG. 10B, again, two robots are provided formeasuring device 17 and working device 18 but they are physicallyseparated from each other and from the table 11, such that vibrationsgenerated by the working device 18 are not taken over by the measuringdevice 17 and/or table 11 or vice versa.

In the embodiment shown in FIG. 10C, the measuring device 17 and theworking device 18 together are jointly fitted on a head 42 or a robotarm 40. In the head 42, vibration dampers and/or active vibrationcompensating means are then included for preventing reciprocalinfluencing. The table 11 is then fixedly arranged.

In the embodiment shown in FIG. 10D, the working device 18 is attachedon a robot arm 40, while the table 11 with the measuring device 17therein or therebelow is as shown in, for instance, FIG. 8 or 9.

In the embodiment shown in FIG. 10E, the table 11 is attached to a robotarm 40 while the working device 18 and measuring device 17 are attachedon a head 42 as shown in FIG. 10C, but here, the head 42 is fixedlydisposed.

FIG. 11 schematically shows an alternative embodiment of an apparatus 10according to the invention, with which virtually simply and preferablyvirtually fully automatically, an optical element such as a multifocalspectacle glass 50 (only shown by way of example) can be manufacturedfrom a pre-form 1 as shown in, for instance, FIGS. 1-4. With thisapparatus, in a housing 51 are provided, successively, a first workingdevice 18A in the form of a milling device, a second working device 18Bin the form of a fluid jet device 19, a third working device 18C, acoating and engraving device and a fourth working device 18D, apolishing device. Here, the holder 16 with at least a part of themeasuring device 17 has been included in a transport means 52,schematically indicated by a trolley, movable over a rail 53, with whichthe pre-form 1 can be moved along the working devices 18A-D. However, itwill be clear that many alternatives are possible to that end, forinstance a carrousel, while naturally, also the working devices can bemoved along a stationarily disposed table 11 with holder 16 and pre-form1.

In a manner described hereinabove, a pre-form 1 is arranged on a holder-16, on the transport means 52, above the measuring device 17. Thestarting form and position are determined and stored in a control unit26, whereupon the transport means 52 is moved into the housing 51, asfar as the first working device 18A. With this, if required, the firstsurface 2 of the pre-form 1 is worked. A milling device 54 for,substantially, the desired final shape is pressed into the first surface2, so that substantially the desired configuration of the first surface2A is obtained. Thereupon, the transport means 52 with the pre-form 1 ismoved to the second working device, in which, with the jet nozzle ornozzles 24 the, optionally, milled surface is polished and/or a recess 7or other local change in surface is provided. Optionally, blowing means(not shown) can be provided for removing grindings, fluid rests and thelike.

In the third working device 18C, means 55 can be provided for applying acoating, for instance for obtaining a reflective or, conversely,non-reflective layer. In this working device 18C, also a blasting device19 can be provided with which the applied coating can be removed, atleast locally, as schematically shown in FIGS. 13 and 14, for marking ofthe object 1, for instance for the purpose of determining position forthe optician or other (eventual) user, or for commercial purposes, forinstance branding.

Finally, the fourth working device 18D is provided with a grindinginstrument 56 for cutting or grinding the pre-form 1 into the desiredshape for obtaining the desired optical element 50. This can, forinstance, be directly ready to be placed into a frame. To that end, oneof the working devices 18, for instance the second, 18B, or the fourth,18D, can be designed for, for instance, providing attachment holes forscrews or other frame parts, grooves in a side of the lens 50 and thelike.

It will be clear that in a working apparatus 10 according to FIG. 11,other numbers and types of working devices can be provided. Forinstance, the coating means 55 can be omitted or the holder can bedesigned such that another side of the pre-form can be worked, or bothsides. In particular there, where pre-forms 1 are used as shown in FIGS.1 and 3, a particularly simple holder 16 can be used, in which or onwhich the pre-form 1 is laid and is supported only along the outercontour. Accordingly, the accessibility of the two surfaces isincreased.

In FIG. 12, as an example, an optic forming element 60 is shown,suitable for use when manufacturing lenses, in particular contactlenses. The male part of a mold is shown. In the forming surface 61,this is provided with a spherical surface 62 which is located slightlymore elevated relative to the forming surface 61. Therefore, with it,while using for instance a female counterpart with a spherical concavesurface, a lens can be formed with relatively thicker edges and athinner central part, at least changing wall thickness. Bu using anapparatus according to the invention, such a forming surface withelevation can be manufactured particularly accurately and in areproducible manner, at relatively low costs. Moreover, in a simplemanner, two or more recesses (not shown) can be provided in a surface,in particular the convex surface of the mold, such that at the concaveside of a lens to be formed therein, at least two spaced apartelevations are provided. During use, these elevations serve aspositioning elements with which rotation on the eye is prevented. Thisis in particular of importance when the lenses are not rotationsymmetrical.

In FIGS. 13 and 14, in top plan view and in cross-sectional side view, alens 50, at least optical element from which a lens 50 can be cut isshown, provided with a coating 57 with marking points 58 therein and anengraved name 59, for instance a brand, a type indication or the like.With an apparatus according to the invention such a marking or brandingcan simply be provided in that the thickness of the coating layer can bedetermined very accurately and the working apparatus, in particular theblasting device 19, can be driven such that only the coating is removedand not a part of the surface on which this has been applied.

With an apparatus 10 according to the invention, in particular as shownin FIG. 11, virtually instantaneously and from a limited number ofpre-forms, an optician or such can manufacture a wide variety of glassesand lenses which can be directly placed into a frame. Moreover, theselenses can be mono as well as bifocal and be individually adjusted.Optionally, the apparatus 10, in particular the control device 26 can bedesigned such that at any moment the user can observe the progressionand/or influence the working.

Naturally, when using, for instance, overmold or undermold techniques,an object 1 to be worked can also be engaged at the peripheral edge sothat both the convex and the concave surface are free to be worked.

It will be clear that with an apparatus according to the invention ormethods or forming elements described herein such as molds for pre-formsor lenses can be formed and/or worked, for instance for aspherical ortoric adjustments of forming surfaces. Also, differently shaped lensescan be made to fit an end user with a method or apparatus according tothe invention, for instance individualized and/or to fit a frame.

The invention is not limited in any manner to the exemplary embodimentsrepresented in the description and the drawing. Many variations thereonare possible within the framework of the invention as outlined by theclaims.

For instance, many other types and forms of pre-forms can be worked withan apparatus or method according to the invention, for instance colored,hardened or with a different starting form. Also, reflective layers canbe provided and worked. By varying the angle between the jet of thefluid jet device and the surface to be worked, the abrasive action canbe influenced and a strongly material-removing or not stronglymaterial-removing or a polishing function for that matter can beobtained. As a result of this too, with an apparatus or method accordingto the invention, any desired working can be carried out, which, eachtime in situ, can be registered and adjusted. Customary polishing meanssuch as polishing heads and polishing pads can be used in addition to orinstead of the fluid jet polishing device, for instance for rapidlypolishing large surfaces, while the blasting device is used for highlycurved and/or irregularly formed and/or locally relatively deep surfaceparts. Also other measuring devices can be used and, for instance, aholder can be used having specific light-passing openings for themeasuring device. As schematically shown in FIG. 10, the measuringdevice can also be designed to be placed above the surface to be worked.For instance, measurement of thickness and changes of thickness can thenalso be measured by reflection on the opposite surface and/or a surfaceof the holder. Other means can be provided for holding the pre-formduring working, for instance clamping means.

All combinations of parts of exemplary embodiments shown and/ordescribed here are understood to fall within the framework of theinvention as outlined by the claims.

1. An apparatus for forming or working optical objects, comprising aworking device, at least one measuring device and a control device, theworking device being adapted to form a surface of the optical object bymachining or abrading, the at least one measuring device is adapted tomeasure changes in form and/or surface roughness of the surface duringthe surface being formed, the measuring device being further adapted toprovide measuring data to the control device, the control device beingadapted to control said working device on the basis of the measuringdata, wherein at least one holder is provided for holding the object tobe worked in the apparatus, which holder is at least partly translucentwhile at least one light source and at least one light receiver aredisposed adjacent said holder, such that during use, light from saidlight source can be sent through said holder and an element locatedthereon and at least light from the light source reflected by thesurface to be worked can be captured by said light receiver, whilemeasuring means are provided for determining absolute and/or relativechanges in the surface of said object to be worked from said reflectedlight captured in said light receiver.
 2. An apparatus according toclaim 1, wherein the measuring device is designed for measuring saidchanges in form with the aid of light beams.
 3. An apparatus accordingto claim 2, wherein the measuring device is designed for measuring saidchanges in form with the aid of interference measurement.
 4. Anapparatus according to claim 2, wherein the measuring device is designedfor measuring changes in roughness.
 5. An apparatus according to claim4, wherein the measuring device is designed for measuring the changes inroughness through scatterometry.
 6. An apparatus according to claim 1,wherein said working apparatus is provided with at least one jet nozzle,the jet nozzle being able to dispense under pressure, a blasting agentfor removing surface material through abrasive action, such that as aresult thereof desired change in form and/or surface roughness isobtained.
 7. An apparatus according to claim 6, wherein said workingapparatus is designed for blasting, under a pressure of between 4 and100 bar, a blasting agent against a surface to be worked.
 8. Anapparatus according to claim 7, wherein the pressure is between 4 and 25bar.
 9. An apparatus according to claim 8, wherein the pressure isbetween 5 and 10 bar.
 10. An apparatus according to claim 7, wherein theblasting agent is a mixture or suspension of a liquid such as water andan abrasive agent such as sand or glass or such solid substance.
 11. Anapparatus according to claim 1, wherein the holder is provided with asurface for attachment of said object with the aid of a blockingcompound which is translucent, such that a first surface of the elementfacing away from the holder can be worked with the working apparatuswhile, at the opposite side of the object, light can be sent through theholder and through the object to be worked.
 12. An apparatus accordingto claim 1, wherein in the holder at least one optical element such as alens is included, in particular a Fresnel lens, while one or more lightsources and light receivers are arranged below the holder for reflectinglight through the holder against the surface of the object to be worked,while the holder has dimensions such that it is substantially covered bythe element.
 13. An apparatus according to claim 1, wherein theapparatus comprises at least milling means, grinding means and/orpolishing means, while at least the grinding means and/or the polishingmeans comprise fluid jet polishing means.
 14. An apparatus according toclaim 1, wherein further, a device is provided for grinding therespective object, designed as a lens, into a frame, while abrasiveworking means are provided for locally working at least one part of atleast one surface of the respective object, the arrangement being suchthat the respective object is substantially concave, while therespective part is substantially convex.
 15. An apparatus according toclaim 1, wherein the apparatus is provided with means for insulating themeasuring device against vibrations in relation to the working devicesuch that, when the optical object is being worked, the measuringresults of the measuring device are not affected by vibrations caused bythe working apparatus.
 16. An apparatus according to claim 15, whereinthe means for insulating against vibrations comprise active and/orpassive damping means.
 17. An apparatus according to claim 15, whereinthe working device comprises a first arm, arranged so as to be insulatedagainst vibrations relative to a holder for the element to be worked andthe measuring device.
 18. An apparatus according to claim 17, whereinthe measuring device is provided, at least partly, on a second arm. 19.An apparatus according to claim 1, wherein the working device isprovided with at least one series of blowing openings through which,during use, a fluid with a grinding agent can be blown out underpressure, for abrasively working a surface.
 20. An apparatus accordingto claim 19, wherein in different blowing openings of the series ofblowing openings select ones of flow rate, pressure, outflow velocityand outflow profile are actively controlled, depending on the measuringdata registered by the measuring device.
 21. An apparatus for forming orworking an optical object, the apparatus comprising: a working devicefor forming a surface of the optical object by machining or abrading; atleast one measuring device for measuring changes in at least one of formand surface roughness of the surface while the surface is being formed;and a control device for controlling said working device on the basis ofthe measuring data, the measuring device providing measuring data to thecontrol device, wherein the working device is provided with at least oneseries of blowing openings through which, during use, a fluid with agrinding agent can be blown out under pressure, for abrasively working asurface, wherein select ones of flow rate, pressure, outflow velocityand outflow profile are actively controlled from different blowingopenings of the series of blowing openings, depending on the measuringdata registered by the measuring device.